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Alves RLOR, Silva LOE, Silva MAD, Consentini CEC, Gonçalves JRS, Melo LDFE, Rodrigues MB, Sartori R. Timed-artificial insemination protocols for Bos indicus beef heifers: Evaluation of protocol length and variations in prostaglandin F2α treatments. Theriogenology 2024; 223:122-130. [PMID: 38723426 DOI: 10.1016/j.theriogenology.2024.04.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 04/26/2024] [Accepted: 04/29/2024] [Indexed: 05/18/2024]
Abstract
The aim was to compare reproductive outcomes of Nelore heifers submitted to timed AI (TAI) protocols, with 7 or 9 d of permanence of the intravaginal progesterone (P4) device and different times of prostaglandin F2α (PGF) administration, for first (n = 935) and second (n = 530) services. On Day -24, heifers without corpus luteum (CL) underwent a protocol for induction of ovulation. On Day 0, heifers received a P4 device (0.5 g) and 1.5 mg estradiol (E2) benzoate. In order for the TAI to be carried out on the same day, these treatments were performed 2 d later on the heifers treated with the 7-d protocol. Additionally, heifers received 0.5 mg PGF at different times, resulting in four experimental groups: 9dP4-PGFd9 (n = 365); 9dP4-PGFd7 (n = 369); 9dP4-PGFd0&9 (n = 364); 7dP4-PGFd0&7 (n = 367). These nomenclatures indicate for how many d the P4 device was kept and the specific day on which PGF was given. At P4 removal, all heifers received 0.5 mg E2 cypionate and 200 IU eCG, and TAI was performed 2 d later. Effects were considered significant when P ≤ 0.05 (superscript letters a,b) whereas a tendency was assumed when 0.05 < P ≤ 0.10. Groups 9dP4-PGFd0&9 and 7dP4-PGFd0&7 had lower percentage of heifers with CL at P4 removal. The diameter (mm) of the dominant follicle (DF) was affected by treatment at P4 removal (9dP4-PGFd9: 11.3 ± 0.3b; 9dP4-PGFd7: 11.8 ± 0.2ab; 9dP4-PGFd0&9: 12.6 ± 0.2a; 7dP4-PGFd0&7: 10.8 ± 0.2c) and at TAI (9dP4-PGFd9: 12.7 ± 0.3ab; 9dP4-PGFd7: 13.2 ± 0.2a; 9dP4-PGFd0&9: 13.4 ± 0.2a; 7dP4-PGFd0&7: 12.4 ± 0.3b). Expression of estrus (%) was affected by treatment (9dP4-PGFd9: 89.6a; 9dP4-PGFd7: 93.5a; 9dP4-PGFd0&9: 88.2ab; 7dP4-PGFd0&7: 85.6b). There were no differences among treatments for P/AI on Day 40 (30-35 d post AI), final P/AI (between Day 70 and parturition) and pregnancy loss (between Day 40 and final P/AI). When the permanence of the P4 device was compared, regardless of PGF treatments, 9-d protocols resulted in greater DF diameter at P4 removal and at TAI, and greater expression of estrus (90.4 vs. 85.6%) than the 7-d protocol. Despite that, the 7-d protocol resulted in greater P/AI on Day 40 (55.3 vs. 49.1%). In addition, there was an interaction between protocol duration and body weight, in which heavier heifers (≥ 307 kg) had greater P/AI when treated with the 7-d protocol, in comparison to 9-d. In conclusion, longer TAI protocols (9 d of P4 device duration) resulted in greater DF diameter and expression of estrus. However, the shorter TAI protocol (7 d of P4 device duration) produced greater P/AI on Day 40, particularly in heavier heifers. Within 9-d protocols, the additional dose of PGF on Day 0 or the anticipation of the PGF to Day 7 did not influence fertility.
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Affiliation(s)
- Rodrigo L O R Alves
- Department of Animal Science, Luiz de Queiroz College of Agriculture, University of São Paulo (ESALQ/USP), Piracicaba, SP, 13418-900, Brazil
| | - Lucas O E Silva
- Department of Animal Science, Luiz de Queiroz College of Agriculture, University of São Paulo (ESALQ/USP), Piracicaba, SP, 13418-900, Brazil
| | - Mateus A da Silva
- Department of Animal Science, Luiz de Queiroz College of Agriculture, University of São Paulo (ESALQ/USP), Piracicaba, SP, 13418-900, Brazil
| | - Carlos E C Consentini
- Department of Animal Science, Luiz de Queiroz College of Agriculture, University of São Paulo (ESALQ/USP), Piracicaba, SP, 13418-900, Brazil; GlobalGen Vet Science, Jaboticabal, SP, 14887-244, Brazil
| | - José R S Gonçalves
- "Hildegard Georgina Von Pritzelwitz" Experimental Station, Londrina, PR, 86010-990, Brazil
| | - Leonardo de F E Melo
- Department of Animal Science, Veterinary and Animal Science School, Federal University of Goiás (UFG), Goiânia, GO, 74001-970, Brazil
| | | | - Roberto Sartori
- Department of Animal Science, Luiz de Queiroz College of Agriculture, University of São Paulo (ESALQ/USP), Piracicaba, SP, 13418-900, Brazil.
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Sanz A, Gobikrushanth M, Colazo MG. Type of CIDR but not eCG administration affected pregnancy per AI in Holstein heifers subjected to a 5-day estrus synchronization protocol. JOURNAL OF APPLIED ANIMAL RESEARCH 2022. [DOI: 10.1080/09712119.2022.2106989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
Affiliation(s)
- Albina Sanz
- Centro de Investigación y Tecnología Agroalimentaria de Aragón (CITA) - IA2 (CITA-Universidad de Zaragoza), Zaragoza, Spain
| | - Mohanathas Gobikrushanth
- Department of Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada
| | - Marcos G. Colazo
- Department of Agricultural Food and Nutritional Science, University of Alberta, Edmonton, Canada
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Filho JT, Pfeifer LFM, Hoefle CA, Rodrigues MF, Ferreira R. Effect of calving to timed artificial insemination interval on fertility of beef cows. Reprod Domest Anim 2022; 57:936-942. [PMID: 35559583 DOI: 10.1111/rda.14156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Accepted: 05/09/2022] [Indexed: 11/28/2022]
Abstract
The objectives of this study were to determine the effect of calving to timed artificial insemination (C-TAI) interval on fertility of Bos taurus and Bos indicus cows, and to determine the best C-TAI interval to include postpartum cows in TAI programs in each genotype (B. taurus and B. indicus). In experiment 1, a retrospective study was performed, with data from 2709 TAI in Bos taurus and Bos indicus cows with different C-TAI intervals. There was a positive linear effect of C-TAI interval on the pregnancy probability (P < 0.0001). However, there was no effect or interaction with the genotype. When C-TAI intervals were grouped in classes, pregnancy rate differed in groups (P < 0,05). Receiver operating characteristic (ROC) analysis was performed and it was observed that 52 days would be the better C-TAI interval to maximize fertility in beef cows. According to previous result, we further stratified into two C-TAI interval groups (≤ 52 days or > 52 days). Cows with C-TAI longer than 52 days (C-TAI>52) had greater pregnancy rate (56%) than cows with short C-TAI (46%; P < 0.01). In experiment 2, 18 postpartum beef cows were subjected to TAI protocol at different C-TAI intervals (n = 6 cows per group): 40, 60 or 80 days postpartum. Cows with 60 days of C-TAI had a greater preovulatory follicle diameter than cows with 80 days postpartum (P < 0.05). The C-TAI interval did not affect (P > 0.05) the ovulation rate nor the proportion of endometrial polymorphonuclear leukocytes. We conclude that C-TAI interval affects pregnancy rate in both Bos taurus and Bos indicus. We recommend a C-TAI interval longer than 52 days to increase fertility of beef cows included in TAI programs.
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Affiliation(s)
- Juarez Tomazi Filho
- Department of Animal Science, Santa Catarina State University, Chapecó, SC, Brazil
| | | | | | | | - Rogério Ferreira
- Department of Animal Science, Santa Catarina State University, Chapecó, SC, Brazil
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